1. Technical Field
This document relates to systems and methods for testing valves. For example, this document relates to systems and methods for accelerated life testing of prosthetic heart valves.
2. Background Information
Accelerated life testing (also known as accelerated wear testing or durability testing) is the process of testing an item by subjecting it to conditions (e.g., cycle time, stress, strain, temperatures, voltage, vibration, pressure, etc.) in excess of its normal service parameters in an effort to uncover faults and potential modes of failure in a reduced amount of time. Accelerated life testing can be been used to study materials, design concepts, design modifications, and durability variations caused by changes in manufacturing techniques.
The ISO 5840-3:2013 standard outlines an approach for qualifying the design and manufacture of heart valve prostheses. ISO 5840-3:2013 requires that mechanical heart valves be tested for at least 600 million cycles (equivalent to 15 years in vivo), and that biological heart valve prostheses be tested for at least 200 million cycles (equivalent to 5 years in vivo) in pulsatile flow simulators using a range of pressures seen in physiologic conditions. The cyclic test must also meet the following two requirements: 1) the test valve must open and close sufficiently each cycle, and 2) during at least 5% of each cycle, the differential pressure across the valve (transvalvular ΔP) must be at least a specified pressure (e.g., 100 mmHg for aortic valves and 120 mmHg for mitral valves).